The Top Three Ways Our Engines Fail

1. Mechanical

 When we think about engine failures, pilots generally presume they’re due to a mechanical issue, and mechanical issues are something for which a mechanic is responsible. Therefore, the thinking often goes, there’s nothing the pilot can do but accept his or her judgment that it will start, run and develop full power when you ask for it. Nope.

In fact, the pilot is the front-line observer of the engine’s health. You’re the one who checks the oil, wiggles the exhaust pipes, looks for oil puddles on the ground and peers into the cowling. You’re also the one who monitors the engine instruments, leans the mixture, advances the propeller control before adding full throttle and opens the cowl flaps on a go-around. You monitor cylinder temperatures to ensure they don’t get too hot and oil temperature to make sure the engine is warm enough to take off in the winter, after preheating it, of course.

If you’re the owner/operator of an engine attached to an aircraft, you’re the one primarily responsible for its airworthiness, not the mechanic. You’re responsible for ensuring all the required inspections are accomplished, that any airworthiness directives are complied with and that any work performed is appropriately documented. If you hold a private certificate or better

When it comes to engines, this refers to such basic things as manufacturer-approved engine oil and filters, spark plugs, etc. It also can refer to maintenance, disassembly and overhaul

Final word about an engine’s mechanical condition: The modern engine monitor is worth its weight in gold when it comes to diagnosing engine issues. The data they record can be downloaded into a spreadsheet and massaged, graphed and otherwise used to identify problems, both short- and long-term. If your airplane doesn’t have one, you’re missing out on one of the best tools available to help you keep your engine running in top shape.

2. Fuel-Related

Fuel-related engine failures generally fall into two categories: Fuel exhaustion, when there’s nothing in the tanks left to burn, and fuel mismanagement, when there’s still fuel aboard but it can’t get to the engine, probably because the pilot did something wrong. Of course, the main thing the pilot often does wrong is to forget to add fuel before take-off.

Starvation is another issue, though, and I can see where a mechanical problem out of your control—like a failed transfer pump—can mean you have a problem. Electric pumps can be pre flighted on the ground, simply by turning on the master, and then the pump switch, and listening.

This chart presents the likelihood of carburettor icing as it relates to temperature and dewpoint.

Note that altitude is not among the variables; it can happen at any height a carburetted engine can reach. Using full carb heat is your first choice. Once you’re convinced the ice is gone, partial heat may be an option. Since warmer air enrichens the fuel mixture, you’ll want to reset that control for extended operations.

3. Carburettor Ice

If you’re a longtime member, you’ve likely read about an engine failure or three where the  engine started and ran fine on the airplane, up to full throttle, without anything done to it after the failure. Having read more than a few accident reports over the years, these events typically have one thing in common: They involved carburetted engines. Yes, the lack of any apparent reason for the engine to fail also occurs with fuel-injected engines, but for different (obviously) reasons, another topic. Of course, by the time someone gets to examine the engine or tries to start it, the offending ice has melted, leaving behind no evidence.

If you fly a carburetted engine, use heat early and often. Apply it periodically to ensure it’s working. Apply it before reducing power

What To Do About It All

An ounce of prevention is worth a pound of cure. The best defence against engine failure is a well-maintained airplane. If it does fail, the best defence against a poor outcome is altitude, which affords you time to troubleshoot the failure and fix it, and/or glide distance to reach a suitable runway. Don’t switch tanks right before take-off, when you’ll have neither time nor glide distance if something happens. Don’t be stingy with the carb heat. Land early to refuel, and stretch your legs, update your weather information, etc.

Read the manufacturer’s documentation and others whose opinion you respect about how to operate the engine, what various abnormalities mean and what you can do about them. Find a good maintenance shop you can trust, preferably one familiar with your aircraft, and listen to them. Ignoring a mechanic’s advice about maintaining  your engine is one way to get real-world engine-out practice.